A battery converts stored chemical energy to electrical energy, which may be conveyed as a voltage source. As a battery ages its storage capacity will decrease (i.e., fade) between a Beginning Of Life (BOL) and an End Of Life (EOL). Therefore, observations of battery parameters such as cycle rate, cumulative cycling time, and storage capacity may be helpful in determining an overall State Of Health (SOH) of a battery over its service life.
To compensate for a battery's low energy transfer rate, some EV systems use Ultracapacitors to provide high energy rates for short durations. For example, in electric vehicles, high energy transfers occur during quick accelerations or regenerative braking. Hybrid ultracapacitor battery systems reduce the overall size of the battery ultracapacitor pair. In such systems, the ultracapacitor bank is configured in a general load sharing arrangement with the battery. Such systems are known to enhance longevity of the battery by removing high energy pulses from the battery and directing them to the ultrcapacitor. In contrast, embodiments discussed herein are not based on a load sharing concept.
High energy charge and discharge pulses on a battery degrade storage capacity and energy delivery characteristics of the battery. In addition, degradation is particularly pronounced when the charge and discharge pulses have very fast rise and fall times.
There is a need for methods and circuits for use with batteries to at least one of determine, detect, and adjust for rapid transitions of charge pulses and discharge pulses from systems coupled to the battery and to adjust the transition rate of such pulses before they reach the battery to reduce degradation that occurs if the transition rate is not adjusted.